Motion sickness is a general denomination of carsickness, seasickness, airsickness and a disease caused by swinging, bumping, rotation, accelerated moving and other various factors. The disease often appears several minutes or hours after riding, navigating, flying and other movements. The patient firstly feels uncomfortable in the upper stomach, then nauseated, looks pale, breaks into a cold sweat; after that, dizziness, mental depression, secreted sputum increase and vomiting may occur, and there may be a blood-pressure decrease, irregular breathing, nystagmus. Serious vomiting may cause deprivation of body fluids and a disorder of electrolytes. Generally, the symptom will disappear or lighten several ten minutes or several hours after stopping the motion or decelerating the velocity. There is also a possibility that the patient can not recover even several days later, and be dispirited, and have limb asthenia. When the motions or accelerations are repeated, the symptoms may reappear.
The disease is mainly related to the function of vestibule. The cysto-ciliary cell of oval vesicle and sphere vesicle of internal ear labyrinth in the vestibule can mainly feel the linear motion up and down, right and left. The ampullary crest ciliary cell of three semicircular canals mainly feel the rotation motion. There are many static cilia and one dynamic cilium in each ciliary cell, the cilia are covered with colloidal membrane consisting of glycoprotein, mucopolysaccharide. The colloidal membrane (anpullae cap, statolithic membrane) can interact with cilia to form a location sensor. When starting or stopping the rotation or linear motion, the displacement of inner lymph will lead to the displacement of the colloid membrane, so applying stimulation to the cilia, and the excitation caused by ciliary cell is passed into cerebra through the vestibular nerve. The ciliary swing of normal person's ciliary cell is in a chaos rhythm, which is very easy to couple and adapt with a random stimulation caused by outside motion. But the ciliary swing of the ciliary cell of a patient suffering from motion sickness is in a quasi-periodicity, so it is difficult to couple with the random stimulation caused by outside motion, leading to a continuous excitation of the ciliary cell, which is transferred from the vestibular nerve to the vestibular nerval nucleus, then transferred to the cerebellum and hypothalamus in proper order, causing a series of clinical symptoms. The stimulation to vestibular may affect the structure of the network, induce the reduction of blood pressure and vomiting. Vestibular nerval nucleus may cause nystagmus from the medial longitudinal fiber to eye muscle motor nuclei; after the cerebellum and hypothalamus suffer from nerval impulse, the change of the muscular tension all over the body will occur. The stimulation to cerebellum may also be another mechanism of this disease.
At present, there is not an effective way for preventing and treating motion sickness. The pending solutions mainly use anti-histamine agents and belladonna agents, or an anti-vomiting agent (metoclopramide), or sedative (such as phenobarbital). These medicaments have large side effects, and bring many inconveniences to trips and to living.